<template>
	<view class="search-box">
		<my-search @on-click="onClickHandler"></my-search>
	</view>
	<view>
		<view class="scroll-view-container">
			<scroll-view class="left-scroll-view" scroll-y :style="{height:wh+'px'}">
				<block v-if="cateList.length" v-for="(item,i) in cateList" :key="i">
					<view :class="['left-scroll-view-item', i === active ? 'active' : '']" @click="activeChanged(i)">
						{{item.cat_name}}
					</view>
				</block>
				<view v-else class="empty-tip">暂无分类数据</view>
			</scroll-view>
			<!-- 右侧滚动视图：放入 flex 容器内，与左侧同级 -->
			<scroll-view class="right-scroll-view" scroll-y :style="{height: wh + 'px'}" :scroll-top="scrollTop">
				<view class="cate-lv2" v-for="(item2,i2) in cateLevel2" :key="i2">
					<view class="cate-lv2-title">{{ item2.cat_name }}</view>
					<!-- 三级列表 -->
					<view class="cate-lv3-list" v-if="item2.children && item2.children.length">
						<view class="cate-lv3-item" v-for="(item3,i3) in item2.children" :key="i3" @click="gotoGoodsList(item3)">
							<image :src="item3.cat_icon" mode="widthFix"></image>
							<text>{{ item3.cat_name }}</text>
						</view>
					</view>
				</view>
			</scroll-view>
		</view>
		</view>
</template>

<script>
	import {
		getCateListApi
	} from '@/api/cate.js'
	export default {
		data() {
			return {
				//wh变量
				wh: 0,
				//分类数据列表
				cateList: [],
				// 当前选中项的索引，默认让第一项被选中
				active: 0,
				//二级分类列表
				cateLevel2: [],
				//滚动条距离顶部的距离
				scrollTop: 0
			};
		},
		onLoad() {
			const sysInfo=uni.getSystemInfoSync();
			this.wh = sysInfo.windowHeight - 50;
			//调用获取分类列表数据的方法
			this.getCateList();
		},
		methods: {
			async getCateList() {
				try {
					const cateData = await getCateListApi();
					//直接赋值
					this.cateList = cateData;
					//为二级分类赋值
					this.cateLevel2 = cateData[0].children;
				} catch (err) {
					// 错误捕获，避免接口异常导致页面崩溃
					console.error('获取分类数据失败：', err);
					uni.showToast({
						title: '数据加载失败，请重试',
						icon: 'none'
					});
				}
			},
			//选中项改变的事情处理函数
			activeChanged(i) {
				this.active = i
				//为二级分类列表重复赋值
				this.cateLevel2 = this.cateList[i].children
				//让 scrollTop 的值在 0 与 1 之间切换
				this.scrollTop=this.scrollTop === 0 ? 1 : 0
				
			},
			gotoGoodsList(item3){
				uni.navigateTo({
					url:'/subpkg/goods_list/goods_list?cid=${cat_id}'
				})
			},
			onClickHandler(){
				uni.navigateTo({
					url:'/subpkg/search/search'
				})
			}
		}
	}
</script>

<style lang="scss" scoped>
	.search-box {
	  // 设置定位效果为“吸顶”
	  position: sticky;
	  // 吸顶的“位置”
	  top: 0;
	  // 提高层级，防止被轮播图覆盖
	  z-index: 999;
	}
	
	.scroll-view-container {
		display: flex;

		// 左侧滑块
		.left-scroll-view {
			width: 120px;

			// 左侧一级分类
			.left-scroll-view-item {
				line-height: 60px;
				background-color: #f7f7f7;
				text-align: center;
				font-size: 12px;

				// 激活项的样式
				&.active {
					background-color: #ffffff;
					position: relative;

					// 渲染激活项左侧的红色指示边线
					&::before {
						content: ' ';
						display: block;
						width: 3px;
						height: 30px;
						background-color: #c00000;
						position: absolute;
						left: 0;
						top: 50%;
						transform: translateY(-50%);
					}
				}
			}
		}

		// 右侧滑块
		.right-scroll-view {

			// 二级分类
			.cate-lv2-title {
				font-size: 12px;
				font-weight: bold;
				text-align: center;
				padding: 15px 0;
			}

			// 三级分类
			.cate-lv3-list {
				display: flex;
				flex-wrap: wrap;

				.cate-lv3-item {
					width: 33.33%;
					margin-bottom: 10px;
					display: flex;
					flex-direction: column;
					align-items: center;

					image {
						width: 60px;
						height: 60px;
					}

					text {
						font-size: 12px;
					}
				}
			}
		}

		.cate-lv2-title {
			font-size: 12px;
			font-weight: bold;
			text-align: center;
			padding: 15px 0;
		}
	}
</style>